The basic purpose of a bookmark is to mark the page at which the reader last left off reading. Most bookmarks serve this purpose admirably, at least to the extent of narrowing the choice down to two pages (i.e. the left-hand and the right-hand, when the book lies open at the marker).
There is a need, however, particularly among students and other readers of complex literature, to mark not only the particular page, but also the particular passage of text on that page to which the reader later wishes to return. The reader may wish to find this precise passage because that is where he or she last left off reading or because the passage contains material to which easy access for later reference is desired. In the latter case, more than one passage may need to be marked.
There is also a need to reference or signal the general subject matter of marked passages, which reference may be interpreted while the book lies closed.
Conventional bookmarks are inadequate to serve these additional needs of discerning readers.
Prior developments in this field may be generally illustrated by reference to the following patents:
______________________________________ Patent No. Patentee Issue Date ______________________________________ 3,011,471 J. C. Tam 12/05/61 3,898,951 G. M. Clare 08/12/75 4,574,727 R. P. Martin, Jr. 03/11/86 2,591,094 J. O'Neill 04/01/52 1,322,796 M. J. Kissel 11/25/19 4,507,830 I. Dahan 04/02/85 4,505,219 M. G. Mangano 03/19/85 ______________________________________
U.S. Pat. No. 3,898,951 teaches a bookmark in which hook and loop fastener material, such as that sold under the trademark VELCRO, is used.
U.S. Pat. Nos. 2,591,094, 4,574,727 and 3,011,471 teach bookmarks which adhere to the book spine, wherein the bookmark is looped over the page.
U.S. Pat. No. 1,322,796 teaches a bookmark which has tips on the ends of two strings.
U.S. Pat. No. 4,507,830, while not really a bookmark, is classified with the bookmark art. It shows a string with non-moveable (col. 2, line 67) beads that can be used to retain sheet material, such as maps.